U.S. patent number 8,015,822 [Application Number 12/275,318] was granted by the patent office on 2011-09-13 for method for controlling an exhaust gas recirculation system.
This patent grant is currently assigned to General Electric Company. Invention is credited to Elizabeth F. Brown, Jatila Ranasinghe.
United States Patent |
8,015,822 |
Ranasinghe , et al. |
September 13, 2011 |
Method for controlling an exhaust gas recirculation system
Abstract
The present invention takes the form of a method and system that
may reduce the level of SOx emissions by recirculating a portion of
the exhaust of at least one turbomachine; the portion of exhaust
may be mixed with the inlet air prior to re-entering the
turbomachine. The present invention may incorporate an inlet bleed
heat system to reduce the likelihood of the liquid products forming
from SOx emissions. Here, a method may maintain a temperature of
the inlet fluid above a condensation temperature.
Inventors: |
Ranasinghe; Jatila
(Simpsonville, SC), Brown; Elizabeth F. (Simpsonville,
SC) |
Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
42114791 |
Appl.
No.: |
12/275,318 |
Filed: |
November 21, 2008 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100126181 A1 |
May 27, 2010 |
|
Current U.S.
Class: |
60/772; 60/785;
60/39.5 |
Current CPC
Class: |
F02M
26/40 (20160201); F02C 3/34 (20130101); F02M
26/06 (20160201); F02M 26/23 (20160201); F02M
35/10268 (20130101); F02C 1/08 (20130101); F02M
26/35 (20160201); F05D 2260/61 (20130101); F02M
35/10157 (20130101); F05D 2270/082 (20130101) |
Current International
Class: |
F02C
1/00 (20060101) |
Field of
Search: |
;60/39.12,39.5,39.52,772,785 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Casaregola; Louis
Assistant Examiner: Wongwian; Phutthiwat
Attorney, Agent or Firm: Davis; Dale J. Cusick; Ernest G.
Landgraff; Frank A.
Claims
What is claimed is:
1. A method of reducing a likelihood of a liquid product forming
within an exhaust stream, wherein the exhaust stream is generated
by a turbomachine; the method comprising: providing a turbomachine
comprising: an inlet bleed heat (IBH) system for increasing a
temperature of an inlet fluid, wherein the inlet fluid comprises an
inlet air and an exhaust stream; wherein the IBH system comprises
at least one valve; a compressor which receives and compresses the
inlet fluid from the IBH system; a recirculation loop which
recirculates the compressed inlet fluid from the compressor to the
IBH system; providing at least one exhaust gas recirculation (EGR)
system comprising at least one of: an EGR skid, and an EGR flow
control device; wherein the EGR system operationally reduces a
concentration of a SOx constituent within the exhaust stream;
utilizing the IBH system to increase a temperature of the inlet
fluid above a condensation temperature; operating the IBH system in
a manner that maintains a temperature of the SOx constituent above
a SOx condensation temperature to reduce a likelihood of formation
Sulfuric Acid forming, wherein Sulfuric Acid accelerates corrosion
and foulin.about. on components of the compressor that ingests the
inlet fluid; and modulating at least one flow control device to
adjust a flowrate of the exhaust stream.
2. The method of claim 1, further comprising determining whether at
least one ambient temperature is within a first margin.
3. The method of claim 2, wherein the at least one ambient
temperature comprises at least one of: a dry bulb temperature, a
wet bulb temperature, or combinations thereof.
4. The method of claim 2, wherein the first margin comprises a
range of at least 5 degrees Fahrenheit above a dew point
temperature.
5. The method of claim 2, wherein if the at least one ambient
temperature is above the first margin then determining whether the
IBH system is operating.
6. The method of claim 5 further comprising decreasing an IBH
flowrate if the IBH system is operating.
7. The method of claim 5, further comprising determining if the at
least one ambient temperature is within a second margin.
8. The method of claim 7, further comprising shutting down the IBH
system if the at least one ambient temperature is within the second
margin.
9. The method of claim 7, further comprising allowing IBH operation
if the at least one ambient temperature is above a second
margin.
10. The method of claim 7, wherein the second margin comprises a
range of at least 15 degrees Fahrenheit above a dew point
temperature.
11. The method of claim 2, wherein the at least one ambient
temperature is within the first margin and then determining whether
the IBH system is operating.
12. The method of claim 8 further comprising increasing an IBH
flowrate if the IBH system is operating.
13. The method of claim 8, further comprising initiating the
operation of the IBH system.
14. The method of claim 1 further comprising: receiving at least
one measurement of a dew point temperature.
15. The method of claim 1 further comprising: receiving at least
one measurement of an ambient temperature.
16. The method of claim 14 further comprising determining at least
one of: a dry-bulb temperature, a wet-bulb temperature, or
combinations thereof.
Description
This application is related to commonly-assigned U.S. patent
application Ser. No. 11/928,038, filed Oct. 30, 2007; U.S. patent
application Ser. No. 11/953,556, filed Dec. 10, 2007; and U.S.
patent application Ser. No. 11/953,525, filed Dec. 10, 2007.
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas recirculation
system, and more particularly to a method and system for
controlling an exhaust gas recirculation system system.
There is a growing concern over the long-term effects of Nitrogen
Oxides (hereinafter NOx) and Carbon Dioxide (hereinafter
"CO.sub.2") and Sulfur Oxides such as, but not limiting of,
SO.sub.2 and SO.sub.3 (hereinafter "SOx") emissions on the
environment. The allowable levels of emissions that may be emitted
by a turbomachine, such as a gas turbine, are heavily regulated.
Operators of turbomachines desire methods of reducing the levels of
NOx, CO.sub.2, and SOx emitted.
Exhaust gas recirculation (EGR) generally involves recirculating a
portion of the emitted exhaust through an inlet portion of the
turbomachine. The exhaust is then mixed with the incoming airflow
prior to combustion. The EGR process facilitates the removal and
sequestration of concentrated CO.sub.2, and may also reduces the
NOx and SOx emission levels.
Generally, the EGR process concentrates CO.sub.2 in the exhaust
stream, and reduces the exhaust stream volume such that CO.sub.2
may be more easily sequestered in a downstream process. However,
there is a similar impact of concentrating any sulfur contained in
the fuel. Sulfur reacts with oxygen to produce SOx in the exhaust
stream, which upon recirculation becomes more concentrated. The
saturated and cooled exhaust stream is mixed with ambient air,
creating an inlet fluid, inside the gas turbine inlet. Here a
generated condensate drops out containing sulfuric acid, which may
corrode compressor blades if carried downstream into the compressor
inlet.
Significant amounts of condensable vapors exist in the exhaust gas
stream. These vapors usually contain a variety of constituents such
as water, acids, aldehydes, hydrocarbons, sulfur oxides, and
chlorine compounds. Left untreated, these constituents will
accelerate corrosion and fouling of the internal components if
allowed to enter the gas turbine.
There are a few concerns with the currently known EGR systems.
Impurities and moisture within the exhaust gas prevent utilizing a
simple re-circulating loop to reduce the generation of emissions,
such as SOx emissions. Turbine fouling, corrosion, and accelerated
wear of internal turbomachine components would result from
introducing the exhaust gas directly to an inlet portion of the
turbomachine. As a result, the diverted exhaust gas should be
treated prior to blending with the inlet air.
For the foregoing reasons, there is a need for a method for
controlling an EGR system. The method should reduce the level of
the liquid products derived from SOx emissions. The method should
seek to maintain a temperature of the inlet fluid above a
condensation temperature.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with an embodiment of the present invention, a method
of reducing a likelihood of a liquid product forming within an
exhaust stream, wherein the exhaust stream is generated by a
turbomachine; the method comprising: providing a turbomachine
comprising: an inlet bleed heat (IBH) system for increasing a
temperature of an inlet fluid, wherein the inlet fluid comprises an
inlet air and an exhaust stream; wherein the IBH system comprises
at least one valve; a compressor which receives and compresses an
inlet fluid from the inlet system; providing at least one exhaust
gas recirculation (EGR) system comprising at least one of: an EGR
skid, and an EGR flow control device; utilizing the IBH system to
increase a temperature of the inlet fluid above a condensation
temperature; and modulating the at least one flow control device to
adjust a flowrate of the exhaust stream.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustrating the environment in which an
embodiment of the present invention operates.
FIGS. 2A and 2B, collectively FIG. 2, is a flowchart illustrating a
method of reducing the level of the liquid products derived from
SOx emissions.
FIG. 3 is a block diagram of an exemplary system of utilizing an
EGR system to reduce the level of the liquid products derived from
SOx emissions in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description of preferred embodiments refers
to the accompanying drawings, which illustrate specific embodiments
of the invention. Other embodiments having different structures and
operations do not depart from the scope of the present
invention.
Certain terminology is used herein for the convenience of the
reader only and is not to be taken as a limitation on the scope of
the invention. For example, words such as "upper," "lower," "left,"
"right," "front", "rear" "top", "bottom", "horizontal," "vertical,"
"upstream," "downstream," "fore", "aft", and the like; merely
describe the configuration shown in the Figures. Indeed, the
element or elements of an embodiment of the present invention may
be oriented in any direction and the terminology, therefore, should
be understood as encompassing such variations unless specified
otherwise.
The present invention has the technical effect of controlling a
system for reducing the concentrations of SOx, NOx, concentrated
CO.sub.2, and other harmful constituents, all of which may be
within a portion of the exhaust (hereinafter "exhaust stream", or
the like). The portion of exhaust may then be mixed with the inlet
air prior to re-entering the turbomachine, without affecting
reliability and availability of the unit. An inlet fluid may be
considered the mixture of the recirculated exhaust stream and the
inlet air. The EGR system may function while the turbomachine is
operating in a mode such as, but not limiting of: spinning reserve,
part load, base load, or combinations thereof.
An embodiment of the present invention takes the form of a system
has the technical effect of reducing the level of the liquid
products derived from SOx emissions. The present invention provides
a method that seeks to maintain a temperature of the inlet fluid
above a condensation temperature.
The present invention may be applied to the variety of
turbomachines that produce a gaseous fluid, such as, but not
limiting of, a heavy-duty gas turbine; an aero-derivative gas
turbine; or the like. An embodiment of the present invention may be
applied to either a single gas turbine or a plurality of
turbomachines. An embodiment of the present invention may be
applied to a turbomachine operating in a simple cycle or a combined
cycle configuration.
Generally, the exhaust gas recirculation system of an embodiment of
the present invention comprises multiple elements. The
configuration and sequence of the elements may be dictated by the
composition of the exhaust gas and the type of cooling fluid used.
In general, the steps comprising the exhaust gas recirculation
process are: diversion, constituent reduction, and mixing.
Referring now to the Figures, where the various numbers represent
like elements throughout the several views, FIG. 1 is a schematic
illustrating the environment in which an embodiment of the present
invention operates. FIG. 1 illustrates a site such as, but not
limiting of a powerplant site, having a turbomachine 100, an EGR
system 150, and a heat recovery steam generator (HRSG) 195.
Alternatively, the present invention may be integrated with a site
not having the HRSG 195.
In an embodiment of the present invention, the EGR skid 175 may use
a fluid that may include: fresh water, seawater, or combinations
thereof to cool the exhaust stream 165. An embodiment of the
present invention may blend sea water and fresh water prior to
introduction into the at least one EGR skid with the goal of
minimizing the impact of the EGR skid fluid characteristics on the
performance of the EGR system 150, The blended fluid may minimize
the impact of variations in the seawater composition.
The elements of the present invention may be fabricated of any
materials that can withstand the operating environment under which
the exhaust gas recirculation system may function and operate.
As described below, an embodiment of the present invention may
utilize at least one EGR skid 175 and an EGR flow control device
170 to recirculate a portion of the exhaust. The EGR skid 175 may
take the form of at least one heat exchanger.
An embodiment of the present invention may incorporate an inlet
bleed heat (IBH) system 190 of a turbomachine 100 with an EGR
system 150. The IBH system 190 may be used in the present invention
to maintain the temperature of the inlet fluid 125 above a
condensation temperature. This may reduce the likelihood of the SOx
condensing into a Sulfuric Acid within the inlet system of the
turbomachine 100, which may lead to corrosion of components of a
compressor 105 of the turbomachine 100.
The turbomachine 100 comprises a compressor 105 having a shaft 110.
Generally, the inlet fluid 125 enters the compressor 105, is
compressed and then discharged to a combustion system 130, where a
fuel 135 such as, but not limiting of, natural gas is burned to
provide high-energy combustion gases 140 which drive the turbine
section 145. In the turbine section 145, the energy of the hot
gases is converted into work, some of which is used to drive the
compressor 105 through the shaft 110, with the remainder being
available for useful work to drive a load (not illustrated). The
total exhaust 120 may exit the turbine section 145 and enter a HRSG
195.
As illustrated in FIG. 1, the turbomachine 100 may also comprise an
IBH 190. Generally, an IBH system 190 removes a portion of the
compressed air in the compressor 105. This may occur for a few
operational purposes. During the start-up of some turbomachines
100, a portion of the air being compressed may be removed to
prevent compressor stall or compressor surge. Here, the IBH system
190 may be used to remove a portion of the compressed air to reduce
the likelihood of those events.
The IBH system 190 may also be used to prevent icing on components
of the compressor 105. Here, the compressed air that is extracted
from the compressor 105 is recirculated to heat the incoming inlet
air 115 above a temperature that may lead to icing of the
components of the compressor 105.
An embodiment of the IBH system 190 may comprise at least one valve
193 and at least one IBH device 199. The at least one valve 193
serves to control the flow of compressed fluid that is extracted
from the compressor 105. The at least one IBH device 199 may
provide at least one measurement of: a wet-bulb temperature,
dry-bulb temperature, specific humidity, relative humidity, or
combinations thereof. In an embodiment of the present invention,
the IBH device 199 may be located within an inlet section of the
turbomachine 100.
The EGR system 150 comprises multiple elements. The configuration
and sequence of these elements may be dictated by the composition
of the exhaust stream 165 and the type of cooling fluid used by the
components of the EGR system 150. Furthermore, alternate
embodiments of the EGR system 150 may include additional or fewer
components than the components described below. Therefore, various
arrangements, and/or configurations, which differ from FIG. 1, may
be integrated with an embodiment of the present invention.
As illustrated in FIG. 1, an embodiment of the EGR system 150 may
comprise: an EGR damper 155, an EGR flow control device 170, an EGR
skid 175, a mixing station 180, a mist eliminator 185, and at least
one constituent feedback device 197.
In use, an embodiment of the EGR system 150 of the present
invention may operate while the turbomachine 100 generates an
exhaust stream 165. The EGR damper 155 may be positioned to allow
for the desired flowrate of the exhaust stream 165, and the
non-recirculated exhaust 160 may flow through an exhaust stack (not
illustrated), or the like. The exhaust stream 165 may then flow
downstream through the EGR flow control device 170, which may take
the form of a fan, blower, or the like.
Next, the exhaust stream 165 may flow to the EGR skid 175. Here,
the exhaust stream 165 may be cooled from a first temperature to a
lower second temperature. The second temperature may allow for the
reduction of some of the SOx emissions. The exhaust stream 165 may
then flow to a mixing station 180, where the exhaust stream 165 may
he mixed with the inlet air 115, forming the inlet fluid 125.
During the mixing process, the temperature of the exhaust stream
165 may be reduced allowing for condensation. Next, the inlet fluid
125 may flow through a mist eliminator 185, which may reduce
condensate droplets within the inlet fluid 125.
Next, the inlet fluid 125 may flow through an inlet section (not
illustrated) of the turbomachine 100. Here, the IBH system 190 may
increase the temperature of the inlet fluid 125 above to a
temperature range that may prevent the inlet fluid 125 from
condensing within the components of the compressor 105.
During the operation of the EGR system 150, a control system may
receive operational data. This may include data on a level of at
least one constituent within the inlet fluid 125 from at least one
constituent feedback device 197. This may also include wet-bulb
temperature data, dry-bulb temperature data, specific humidity
data, relative humidity data which may be received from at least
one IBH device 199, as described. The operational data may be used
to control the operation of the turbomachine 100 and/or the EGR
system 150.
As will be appreciated, the present invention may be embodied as a
method, system, or computer program product. Accordingly, the
present invention may take the form of an entirely hardware
embodiment, an entirely software embodiment (including firmware,
resident software, micro-code, etc.) or an embodiment combining
software and hardware aspects all generally referred to herein as a
"circuit", "module," or " system". Furthermore, the present
invention may take the form of a computer program product on a
computer-usable storage medium having computer-usable program code
embodied in the medium.
Any suitable computer readable medium may be utilized. The
computer-usable or computer-readable medium may be, for example but
not limited to, an electronic, magnetic, optical, electromagnetic,
infrared, or semiconductor system, apparatus, device, or
propagation medium. More specific examples (a non exhaustive list)
of the computer-readable medium would include the following: an
electrical connection having one or more wires, a portable computer
diskette, a hard disk, a random access memory (RAM), a read-only
memory (ROM), an erasable programmable read-only memory (EPROM or
Flash memory), an optical fiber, a portable compact disc read-only
memory (CD-ROM), an optical storage device, a transmission media
such as those supporting the Internet or an intranet, or a magnetic
storage device. Note that the computer-usable or computer-readable
medium could even be paper or another suitable medium upon which
the program is printed, as the program can be electronically
captured, via, for instance, optical scanning of the paper or other
medium, then compiled, interpreted, or otherwise processed in a
suitable manner, if necessary, and then stored in a computer
memory. In the context of this document, a computer-usable or
computer-readable medium may be any medium that can contain, store,
communicate, propagate, or transport the program for use by or in
connection with the instruction execution system, apparatus, or
device.
Computer program code for carrying out operations of the present
invention may be written in an object oriented programming language
such as Java7, Smalltalk or C++, or the like. However, the computer
program code for carrying out operations of the present invention
may also be written in conventional procedural programming
languages, such as the "C" programming language, or a similar
language. The program code may execute entirely on the user's
computer, partly on the user's computer, as a stand-alone software
package, partly on the user's computer and partly on a remote
computer or entirely on the remote computer. In the latter
scenario, the remote computer may be connected to the user's
computer through a local area network (LAN) or a wide area network
(WAN), or the connection may be made to an external computer (for
example, through the Internet using an Internet Service
Provider).
The present invention is described below with reference to
flowchart illustrations and/or block diagrams of methods,
apparatuses (systems) and computer program products according to
embodiments of the invention. It will be understood that each block
of the flowchart illustrations and/or block diagrams, and
combinations of blocks in the flowchart illustrations and/or block
diagrams, can be implemented by computer program instructions.
These computer program instructions may be provided to a processor
of a public purpose computer, special purpose computer, or other
programmable data processing apparatus to produce a machine, such
that the instructions, which execute via the processor of the
computer or other programmable data processing apparatus, create
means for implementing the functions/acts specified in the
flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a
computer-readable memory that can direct a computer or other
programmable data processing apparatus to function in a particular
manner, such that the instructions stored in the computer-readable
memory produce an article of manufacture including instruction
means which implement the function/act specified in the flowchart
and/or block diagram block or blocks. The computer program
instructions may also be loaded onto a computer or other
programmable data processing apparatus to cause a series of
operational steps to be performed on the computer or other
programmable apparatus to produce a computer implemented process
such that the instructions which execute on the computer or other
programmable apparatus provide steps for implementing the
functions/acts specified in the flowchart and/or block diagram
blocks.
The present invention may include a control system, or the like,
that has the technical effect of reducing the level of the liquid
products derived from SOx emissions. The control system may receive
data on the concentration of the at least one constituent from the
at least one constituent feedback device 197. The control system
may also receive data on the wet-bulb temperature, dry-bulb
temperature, specific humidity, relative humidity, or the like from
the at least one IBH device 199. Based in part of the received
data, the control system may adjust to the operation of the EGR
system 150 and/or the IBH system 190.
The control system of an embodiment of the present invention may be
configured to automatically and/or continuously monitor the
turbomachine 100 to determine whether the EGR system 150 should
operate. Alternatively, the control system may be configured to
require a user action to the initiate operation of the EGR system
150. An embodiment of the control system of the present invention
may function as a stand-alone system. Alternatively, the control
system may be integrated as a module, or the like, within a broader
system, such as a turbine control or a plant control system.
FIGS. 2A and 2B, collectively FIG. 2, is a flowchart illustrating a
method of reducing the level of the liquid products derived from
SOx emissions. In an embodiment of the present invention the EGR
system 150 may be integrated with a graphical user interface (GUI),
or the like. The GUI may allow the operator to navigate through the
method 200 described below. The GUI may also provide at least one
notification of the status of the EGR system 150.
In step 205, of the method 200, the turbomachine 100 generates an
exhaust. Depending on either the type and/or operation of the
turbomachine 100, the generated exhaust may have a flowrate, for
example, but not limiting of, of about 10,000 Lb/hr to about
50,000,000 Lb/hr and a temperature of about 100 Degrees Fahrenheit
to about 1500 Degrees Fahrenheit.
In step 210, the method 200 may determine whether at least one
initialization permissive is satisfied. An embodiment of the
present invention may require that the at least one initialization
permissive is satisfied before the EGR system 150 begins to process
the exhaust stream 165. The initialization permissive may generally
be considered a permissive that confirms the turbomachine 100 and
the EGR system 150 are ready to process the exhaust stream 165. In
an embodiment of the present invention, the user may define the at
least one initialization permissive.
The at least one initialization permissive may include at least one
of: preheating status of the EGR system 150; operational readiness
of the EGR system 150 components; status of at least one fault
condition of the EGR system 150; and combinations thereof. If the
at least one initialization permissive is satisfied then the method
200 may proceed to step 215; otherwise the method 200 may revert to
step 205 until the at least one initialization permissive is
satisfied.
In step 215, the method 200 may provide a notification to the user
that the EGR system 150 is initialized and ready to process the
exhaust stream 165. In an embodiment of the present invention, the
GUI may provide the notification as a pop-up window, alarm, or
other similar methods.
Here, the method 200 may proceed on at least two parallel paths. As
illustrated in FIG. 2. After, the initialization permissive is
satisfied, the method 200 may simultaneously proceed to step 215
and step 255.
In step 220, the method 200 may modulate at least one flow control
device. A flow control device may be considered a component of the
EGR system 150 that allows for the exhaust stream 165 to flow
through certain portions of the EGR system 150. The at least one
flow control device may have the form of the EGR damper 155, or the
like.
The EGR damper 155 may divert a portion of the total exhaust 120
generated by the turbomachine 100 to the EGR system 150, where the
diverted portion becomes the exhaust stream 165. For example, but
not limiting of, the EGR damper 155 may open and allow for
diversion of up to 45% of the total exhaust 120 to become the
exhaust stream 165 for the EGR system 150 to receive the exhaust
stream 165.
Referring now to step 225, where the method 200 may adjust the
flowrate of the exhaust stream 165 within the EGR system 150. The
method 200 may utilize at least one EGR control device (not
illustrated) to adjust a flowrate of the exhaust stream 165. The
EGR damper 155 may apportion up to about 45 percent of the total
exhaust 120 to the exhaust stream 165. The efficiency of the EGR
system 150 may be improved if the flowrate of the exhaust stream
165 is increased. The at least one EGR control device may allow the
exhaust stream 165 to overcome the pressure drop of the EGR system
150, allowing for the at least one exhaust stream 165 to flow
throughout the EGR system 150. The at least one EGR control device
may have the form of a fan, blower, or other similar device,
capable of increasing the flowrate of the exhaust stream 165.
The control system may be integrated with a plurality of pressure
transmitters, or the like. The transmitters may be located
throughout 150; and may determine the pressure drop within the EGR
system 150. The control system may receive data on the pressure
drop. The control system may then adjust the speed of the EGR
control device to overcome the pressure drop, as needed.
In step 230, the method 200 may analyze the exhaust constituents to
determine the likelihood of SOx constituents condensing and forming
liquid products.
In step 235 the method 200 may determine whether the aforementioned
constituents are within an acceptable range. The present invention
may utilize a variety of sensors, thermocouples, and other similar
devices to determine the concentration of constituents remaining in
the exhaust stream 165. If the exhaust constituents are within the
range then the method 200 may proceed to step 240; otherwise the
method 200 may revert to step 235.
In step 240, the method 200 may modulate at least one flow control
device to allow for the exhaust stream 165 to re-enter the
turbomachine 100. After the method 200 determines that constituents
are within the acceptable range, the aforementioned flow control
devices may be modulated, as needed.
In step 245, the method 200 may allow for aborting the operation of
the EGR system 150. As illustrated in FIG. 2, the operation of the
EGR system 150 may be aborted after the EGR system 150 has been
initialized in 215. An embodiment of the present invention, may
allow for a user to manually abort the operation of the EGR system
150. Alternatively, the method 200 may be integrated with a system
that allows for the automatic aborting of the operation of the EGR
system 150. If the operation of the EGR system 150 is aborted, then
the method 200 may revert to step 205, otherwise the method 200
proceeds to the next step.
In step 250, the method 200 may determine whether at least one
operational permissive is maintained during the operation of the
EGR system 150. Step 250 may be continuously monitoring the
operation of the EGR system 150.
The operational permissive may include at least one of: an EGR
fraction; a concentration range of at least one constituent; the
EGR skid 175 is operating within an operational range; a status of
at least one fault condition of the EGR system 150; a combustion
dynamics margin; a compressor stall and/or surge margin; and
combinations thereof.
In an embodiment of the present invention, the GUI may notify the
user if the operational permissive is not maintained. In an
alternate embodiment of the present invention, the method 200 may
automatically revert to step 205 if the operational permissive is
not maintained.
The EGR skid 175 may reduce the temperature of the exhaust stream
165 to around a saturation temperature. This may allow for the
turbomachine 100 to maintain the steady gas turbine output by
increasing inlet mass flow. Cooling of the exhaust stream 165
typically results in a higher mass flow of exhaust per unit volume
entering the compressor 105. The cooling of the exhaust stream 165
may result in the turbomachine 100 generating a higher output and
not experiencing a decrease in performance as may occur with a
higher average inlet temperature of the inlet fluid.
The cooling process may also allow for the sequestration and
removal of some of the concentrated SOx constituent in the exhaust
stream 165. The EGR skid 175 may reduce the exhaust stream 165 to a
range of about 35 degrees Fahrenheit to about 100 degrees
Fahrenheit.
The method 200 may utilize additional components to remove
particulates and/or other constituents from the exhaust stream 165.
The additional components may also reduce the temperature of the
exhaust stream 165 to allow for the particulate to be removed by
condensation of the exhaust stream 165, during the aforementioned
cooling process. The additional components may include at least one
of the mixing station 180 and the mist eliminator 185; which were
previously described.
An embodiment of the present invention may utilize the IBH system
190 in conjunction with the EGR system 150 to bring the SOx
concentration within a desired range. As described below, the EGR
skid 175 may remove a portion of the SOx containments. Then, the
IBH system 190 may prevent the formation of Sulfuric Acid, which
may form on the compressor 105 if the inlet fluid 125, comprising
SOx, condenses.
An embodiment of the present invention may utilize at least one
device to determine the wet-bulb and dry-bulb temperatures. These
temperatures may be used to control the operation of the IBH system
190. Here, the valve 193 of the IBH system 190 may be adjusted to
provide sufficient heat to maintain the temperature of the inlet
fluid 125 above a condensation temperature. An example of this
process is described in steps 255 through 295 of FIG. 2B.
In step 255, the method 200 may determine whether the relative
humidity, wet bulb temperature, or the like is above a first
margin. Here, the method 200 may receive data on the ambient
conditions. This data may include the wet-bulb temperature, the dry
bulb, temperature, or the like. The control system may seek to
maintain a margin above the condensation temperature of the inlet
fluid 125. For example, but not limiting of, the first margin may
be approximately 5 degrees Fahrenheit or greater above a dew point
temperature. If the ambient temperature is not above the first
margin, then the method 200 may proceed to step 265; otherwise the
method 200 may proceed to step 285.
In step 260, the method 200 may determine wherein an IBH system 190
is operating (as described) with the valve 193 at a minimum
position. Here the method 200 may determine that too much IBH flow
is being provided. If the IBH system 190 is operating then the
method 200 may proceed to step 265; otherwise the method 200 may
proceed to step 270.
In step 265, the method 200 may decrease the flowrate of the IBH
system 190. Here the control system may stroke the valve 193
towards a closed position.
In step 270, the method 200 may determine whether the ambient
temperature is within a second margin. Here, the method 200 may
determine whether enough margin exists between the ambient
temperatures and dew point to allow further closing of the valve
193. The second margin may be considered a minimum range that will
maintain an allowable margin above the ambient dew point
temperature. For example, but not limiting of, the second margin
may be approximately 15 degrees Fahrenheit or greater above a dew
point temperature. If the ambient temperature is within the second
margin, then the method 200 may proceed to step 275; otherwise the
method 200 may proceed to step 280.
In step 275, the method 200 may shutdown the IBH operation. This
may increase the overall efficiency of the turbomachine 100 by
reducing the amount of compressed air being extract from the
compressor 105.
In step 280, the method 200 may allow the IBH system 190 to
maintain the current operation. This may seek to ensure that the
inlet fluid 125 is operating a temperature above the dew point,
minimizing the likelihood of condensate forming in the compressor
105.
Referring now to step 285. The method 200, in step 255, may have
determined that the ambient temperatures are not above a first
margin. In step 285, the method 200 may determine whether the IBH
system 190 is operating. The control system may receive feedback on
the operational status on the IBH system 190. If the IBH system 190
is operational, then the method 200 may proceed to step 290;
otherwise the method 200 may proceed to step 295.
In step 290, the method 200 may increase the IBH flowrate. Here,
the control system may increase the stroke of the valve 193.
In step 295, the method 200 may initiate the operation of the IBH
system 190. Here, the control system may increase the stroke of the
valve 193 to the minimum position for IBH operation.
FIG. 3 is a block diagram of an exemplary system 300 of utilizing
an EGR system to reduce the level of the liquid products derived
from SOx emissions in accordance with an embodiment of the present
invention. The elements of the method 200 may be embodied in and
performed by the system 300. The system 300 may include one or more
user or client communication devices 302 or similar systems or
devices (two are illustrated in FIG. 3). Each communication device
302 may be for example, but not limited to, a computer system, a
personal digital assistant, a cellular phone, or similar device
capable of sending and receiving an electronic message.
The communication device 302 may include a system memory 304 or
local file system. The system memory 304 may include for example,
but is not limited to, a read only memory (ROM) and a random access
memory (RAM). The ROM may include a basic input/output system
(BIOS). The BIOS may contain basic routines that help to transfer
information between elements or components of the communication
device 302. The system memory 304 may contain an operating system
306 to control overall operation of the communication device 302.
The system memory 304 may also include a browser 308 or web
browser. The system memory 304 may also include data structures 310
or computer-executable code for utilizing an EGR system 150 that
may be similar or include elements of the method 200 in FIG. 2.
The system memory 304 may further include a template cache memory
312, which may be used in conjunction with the method 200 in FIG. 2
for utilizing an EGR system 150.
The communication device 302 may also include a processor or
processing unit 314 to control operations of the other components
of the communication device 302. The operating system 306, browser
308, and data structures 310 may be operable on the processing unit
314. The processing unit 314 may be coupled to the memory system
304 and other components of the communication device 302 by a
system bus 316.
The communication device 302 may also include multiple input
devices (I/O), output devices or combination input/output devices
318. Each input/output device 318 may be coupled to the system bus
316 by an input/output interface (not shown in FIG. 3). The input
and output devices or combination I/O devices 318 permit a user to
operate and interface with the communication device 302 and to
control operation of the browser 308 and data structures 310 to
access, operate and control the software to utilize an EGR system
150. The I/O devices 318 may include a keyboard and computer
pointing device or the like to perform the operations discussed
herein.
The I/O devices 318 may also include for example, but are not
limited to, disk drives, optical, mechanical, magnetic, or infrared
input/output devices, modems or the like. The I/O devices 318 may
be used to access a storage medium 320. The medium 320 may contain,
store, communicate, or transport computer-readable or
computer-executable instructions or other information for use by or
in connection with a system, such as the communication devices
302.
The communication device 302 may also include or be connected to
other devices, such as a display or monitor 322. The monitor 322
may permit the user to interface with the communication device
302.
The communication device 302 may also include a hard drive 324. The
hard drive 324 may be coupled to the system bus 316 by a hard drive
interface (not shown in FIG. 3). The hard drive 324 may also form
part of the local file system or system memory 304. Programs,
software, and data may be transferred and exchanged between the
system memory 304 and the hard drive 324 for operation of the
communication device 302.
The communication device 302 may communicate with at least one unit
controller 326 and may access other servers or other communication
devices similar to communication device 302 via a network 328. The
system bus 316 may be coupled to the network 328 by a network
interface 330. The network interface 330 may be a modem, Ethernet
card, router, gateway, or the like for coupling to the network 328.
The coupling may be a wired or wireless connection. The network 328
may be the Internet, private network, an intranet, or the like.
The at least one unit controller 326 may also include a system
memory 332 that may include a file system, ROM, RAM, and the like.
The system memory 332 may include an operating system 334 similar
to operating system 306 in communication devices 302. The system
memory 332 may also include data structures 336 for utilizing an
EGR system 150. The data structures 336 may include operations
similar to those described with respect to the method 200 for
utilizing an EGR system 150. The server system memory 332 may also
include other files 338, applications, modules, and the like.
The at least one unit controller 326 may also include a processor
342 or a processing unit to control operation of other devices in
the at least one unit controller 326. The at least one unit
controller 326 may also include I/O device 344. The I/O devices 344
may be similar to I/O devices 318 of communication devices 302. The
at least one unit controller 326 may further include other devices
346, such as a monitor or the like to provide an interface along
with the I/O devices 344 to the at least one unit controller 326.
The at least one unit controller 326 may also include a hard disk
drive 348. A system bus 350 may connect the different components of
the at least one unit controller 326. A network interface 352 may
couple the at least one unit controller 326 to the network 328 via
the system bus 350.
The flowcharts and step diagrams in the figures illustrate the
architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments of the present invention. In this
regard, each step in the flowchart or step diagrams may represent a
module, segment, or portion of code, which comprises one or more
executable instructions for implementing the specified logical
function(s). It should also he noted that, in some alternative
implementations, the functions noted in the step may occur out of
the order noted in the figures. For example, two steps shown in
succession may, in fact, be executed substantially concurrently, or
the steps may sometimes be executed in the reverse order, depending
upon the functionality involved. It will also be noted that each
step of the step diagrams and/or flowchart illustration, and
combinations of steps in the step diagrams and/or flowchart
illustration, can be implemented by special purpose hardware-based
systems which perform the specified functions or acts, or
combinations of special purpose hardware and computer
instructions.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
Although specific embodiments have been illustrated and described
herein, it should be appreciated that any arrangement, which is
calculated to achieve the same purpose, may be substituted for the
specific embodiments shown and that the invention has other
applications in other environments. This application is intended to
cover any adaptations or variations of the present invention. The
following claims are in no way intended to limit the scope of the
invention to the specific embodiments described herein.
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